Somatic DNA Alterations of the 81 Locus of Oxytricha trifallax: Mechanisms and Evolution of its Alternative Processing

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9600663 Herrick A phylogenetic survey across a spectrum of ciliates will monitor the genesis and molecular evolution of the processing of the 81 locus of Oxytricha fallax. The 81 locus is of particular interest because it has been shown that during the development of the somatic macronucleus it is processed to form three overlapping macronuclear chromosomes. The phylogenetic survey will be done with degenerate-primer PCR of macronuclear intervals representative of alternative processing in the DNAs of ever more distantly related ciliates. The amplified DNAs will be sequenced and analyzed for molecular and relational insights as well as determining the design of further degenerate PCR primers to permit detection of more distantly related sequences. %%% Ciliates process their germline nucleus to produce a somatic nucleus by eliminating specific DNA sequences in a programmed fashion. One particular locus, the 81 locus of Oxytricha falfax, has been shown to be unusual in that it is alternatively processed to produce three overlapping fragments with a total of three open reading frames. This study will use this region for a comparison of the involved sequence in DNA from related hypotrichous ciliated protozoa in the hope of understanding the evolution of programmed gene rearrangements. Such programmed DNA rearrangements are observed in immune-cell gene rearrangements and stochastic rearrangements during tumorigenesis in mammals and insight into the evolution of the process in these simple protozoa can provide a basis of understanding of the process in more complex organisms. ***